/**
* QR Code Generator Service
*
* This file contains the main business logic for the QR generator module.
* Handles QR code generation with various options and formats.
*/
import QRCode from 'qrcode';
import { validateQRInput, formatQRResponse } from './utils.js';
/**
* QR Code service class for handling QR code generation operations
*/
export class QRService {
constructor() {
this.maxTextLength = 4296; // Maximum characters for QR code
this.defaultOptions = {
size: 200,
format: 'png',
errorCorrectionLevel: 'M',
margin: 4,
};
}
/**
* Generate QR code from text
* @param {string} text - Text to encode
* @param {Object} options - Generation options
* @returns {Promise<Object>} - QR code data
*/
async generateQRCode(text, options = {}) {
try {
// Validate input
validateQRInput(text, options);
// Merge with defaults
const config = { ...this.defaultOptions, ...options };
// Prepare QR code options
const qrOptions = {
errorCorrectionLevel: config.errorCorrectionLevel,
type: 'image/png',
quality: 0.92,
margin: config.margin,
color: {
dark: '#000000',
light: '#FFFFFF',
},
width: config.size,
};
let qrData;
let mimeType;
let encoding;
switch (config.format) {
case 'png': {
// Generate PNG buffer
const buffer = await QRCode.toBuffer(text, qrOptions);
qrData = buffer.toString('base64');
mimeType = 'image/png';
encoding = 'base64';
break;
}
case 'svg': {
// Generate SVG string
const svgString = await QRCode.toString(text, {
...qrOptions,
type: 'svg',
width: config.size,
});
qrData = Buffer.from(svgString).toString('base64');
mimeType = 'image/svg+xml';
encoding = 'base64';
break;
}
case 'base64': {
// Generate data URL
const dataURL = await QRCode.toDataURL(text, qrOptions);
qrData = dataURL;
mimeType = 'image/png';
encoding = 'dataurl';
break;
}
default:
throw new Error(`Unsupported format: ${config.format}`);
}
return formatQRResponse({
text,
qrData,
mimeType,
encoding,
options: config,
size: this.calculateQRSize(text, config.errorCorrectionLevel),
});
} catch (error) {
throw new Error(`Failed to generate QR code: ${error.message}`);
}
}
/**
* Get QR code information without generating
* @param {string} text - Text to analyze
* @param {string} errorCorrectionLevel - Error correction level
* @returns {Object} - QR code information
*/
getQRInfo(text, errorCorrectionLevel = 'M') {
try {
validateQRInput(text, { errorCorrectionLevel });
const info = {
textLength: text.length,
maxLength: this.maxTextLength,
estimatedSize: this.calculateQRSize(text, errorCorrectionLevel),
errorCorrectionLevel,
supportedFormats: ['png', 'svg', 'base64'],
supportedErrorLevels: {
L: 'Low (~7% correction)',
M: 'Medium (~15% correction)',
Q: 'Quartile (~25% correction)',
H: 'High (~30% correction)',
},
};
return info;
} catch (error) {
throw new Error(`Failed to get QR info: ${error.message}`);
}
}
/**
* Calculate estimated QR code size (modules)
* @param {string} text - Text to encode
* @param {string} errorCorrectionLevel - Error correction level
* @returns {Object} - Size information
*/
calculateQRSize(text, errorCorrectionLevel) {
// Simplified calculation - actual size depends on encoding mode and content
const baseSize = Math.ceil(Math.sqrt(text.length * 8));
const correctionMultiplier =
{
L: 1.0,
M: 1.15,
Q: 1.25,
H: 1.3,
}[errorCorrectionLevel] || 1.15;
const estimatedModules = Math.max(21, Math.ceil(baseSize * correctionMultiplier));
return {
estimatedModules,
minSize: 21, // QR codes start at 21x21 modules
description: `Estimated ${estimatedModules}x${estimatedModules} modules`,
};
}
/**
* Validate if text can be encoded in QR code
* @param {string} text - Text to validate
* @returns {boolean} - Whether text is valid
*/
canEncode(text) {
try {
validateQRInput(text);
return true;
} catch {
return false;
}
}
/**
* Get supported options
* @returns {Object} - Supported options and their ranges
*/
getSupportedOptions() {
return {
formats: ['png', 'svg', 'base64'],
errorCorrectionLevels: ['L', 'M', 'Q', 'H'],
sizeRange: { min: 50, max: 1000 },
marginRange: { min: 0, max: 10 },
maxTextLength: this.maxTextLength,
defaults: this.defaultOptions,
};
}
}
// Export a singleton instance
export const qrService = new QRService();
